A stack of goods can be packaged by heat shrinking a shrinkable foil covering or envelope on the stack of goods on a pallet.
It comprises a delivery mechanism for drawing a tubular thermoplastic synthetic resin foil from a roll of tubing and which cuts away a piece from the foil tubing and simultaneously closes the top of that piece by an upper end weld seam, and a framelike vertically movable shrinking mechanism which heats all sides of the sheath or envelope covering the stack of goods.
A packaging apparatus can automatically provide a stack of goods with such a shrinkable foil covering and shrink that covering onto the stack.
The foil tubing drawn from a roll of tubing is passed over the stack of goods by feeding it through a spreading mechanism. The folded foil tubing is opened by the spreading mechanism as it is put on the stack of goods. During the cutting away of the piece from the foil tubing which serves as the shrinkable foil covering the end weld seam is simultaneously formed so that the top of the foil covering is closed. The foil covering is subsequently shrunk by infrared radiation or heated air.
The framelike shrinking mechanism is movable in a vertical direction over the stack of goods provided with the shrinkable foil covering. After that heat is applied and the foil covering is shrunk.
During the shrinking process the heat is also transferred to the surroundings. The surrounding air is heated and a strong upwards flow of heated air occurs in and around the shrinking mechanism even if the heating unit is an infrared radiation.
The heated air can reach the delivery mechanism for drawing foil tubing from the roll of tubing located above the stack of goods. Thus there is the danger of premature shrinkage of the piece of foil tubing by convection due to the upwardly flowing heated air.